The present invention relates to clutches in general, and more particularly to improvements in clutch disc arrangements which can be utilized with advantage in friction clutches of automotive vehicles.
A clutch disc arrangement normally comprises a hub which is connected for rotation with two lateral disc-shaped annular guides flanking the radially innermost portion of a clutch disc which carries the customary friction coatings and is rotatable, within limits, relative to the hub. It is also known to provide energy storing devices in the form of coil springs or the like which oppose at least some stages of angular movement of the clutch disc relative to the hub and/or vice versa. For the sake of simplicity, the following description will speak of rotation of the clutch disc relative to the hub with the understanding, however, that the situation is analogous when the hub turns relative to the clutch disc, when the clutch disc and the hub turn in opposite directions or when the hub and the clutch disc turn in the same direction but at different speeds. As a rule, the energy storing devices are mounted between the clutch disc and the guides of the hub. Furthermore, it is already known to install between the clutch disc and the component including the hub and the guides one or more friction generating units which also oppose rotation of the clutch disc relative to the hub. Still further, it is already known to provide such clutch disc arrangements with a so-called load friction unit which is active or effective only after the clutch disc has already completed a certain amount of angular displacement in a clockwise or counterclockwise direction from a neutral angular position with reference to the hub. A conventional load friction unit can comprise at least one friction disc which is installed between the clutch disc and one of the guides as well as a friction generating device (e.g., a friction pad). Still further, the load friction unit can comprise, or it can be associated with, one or more energy storing devices (e.g., additional coil springs) which are interposed between the guides and the friction disc to yieldably oppose at least some stages of angular movement of the friction disc relative to the hub. Reference may be had, for example, to FIGS. 5 and 6 of commonly owned German Pat. No. 24 36 288 granted Oct. 6, 1977. The clutch disc arrangements which are shown in FIGS. 5 and 6 of this German patent employ a clutch disc and two friction discs between the guides on the hub or a single friction disc, a clutch disc at one side of the single friction disc and a further disc which is disposed at the other side of the friction disc and is rigidly connected to the clutch disc. It has been found that the assembly of such clutch disc arrangements is a relatively complex and time-consuming operation, and also that the dimensions of the patented arrangement, as considered in the axial direction of the hub, may not be ideal for use in certain types of friction clutches.